This invention relates to a method for producing a semiconductor laser element, particularly to a method for producing a semiconductor laser element and more having a stripe light emitting region and mirrors for forming a laser resonator which orthogonally cross said light emitting region and are arranged mutually face to face.
A practical semiconductor laser element is realized by the so-called striped structure wherein the light emitting regions are limited to the striped comparatively narrow areas. A laser resonator is indispensable for laser operation and in the semiconductor laser element a pair of mirrors for forming the laser resonator are generally structured at the two element ends which are orthogonally crossing the longitudinal direction of the striped light emitting region. The mirror surface of the laser resonator is required to have an optical flatness. Therefore some ideas have been proposed to make flat the element end surface. Generally, the end surface of these elements, for a laser resonator is made by cleavage of the monocrystal semiconductor wafer comprising the laser element because the cleaved surface of a single crystal wafer is much superior to the ordinary mechanically formed surface in achieving the flatness.
The cleaving process of a wafer is usually carried out without regionally giving a direct mechanical stress to a laser element. A regional stress produces countless minute cracks on the wafer and leaves countless convex and concave areas along the cracks on the cleaved surface, resulting in rough surface. The practical cleaving process is manually conducted in such a way, for example, that a razor blade is put on the wafer end and is driven like a wedge. Therefore, the working efficiency is very bad. The reason is that a semiconductor laser element is generally composed of a small size chip having a side of 1 mm or less. In addition, since it is very difficult to set correctly the cleaving position, the distance between the facing cleaving surfaces, namely a length of the resonator, is difficult to make at a constant value. Of course, the resonator lengths highly influences the oscillation characteristic of the laser element. Thus, in place of the abovementioned conventional method, a novel method which excels in working efficiency and assures a set resonator length with excellent reproducibility is desired.